... In order to obtain a quantitative estimate of the accuracy and reliability of our data reduction procedures and results, we have performed a data reduction pipeline based on the following steps: i) define a set of simulated HST-like images with synthetic globular cluster stellar distributions, which provide the ``true'' data for comparison; ii) convolve these images with appropriate assumptions of PSF and noise in order to construct simulated `` observed '' ... It contains 470 stars. b) ...

... The performance of each algorithm on the simulated lightcurves is scored accor ding to the rates of false positive (Type I) and false negative (Type II) errors. ... Combined: threshold normalization = 5 в 10 -4 References · Aschwanden, M.J., Nightingale, R.W. Tarball, T.D., & Wolfson, C.J. 2000, Ap J , 5 3 5 , 1 0 2 7 · Hudson, H.S. 1991, SoPh, 133, 357 Figure 3 Calibrating the event detection algorithms to optimize false positives, using the simulated lightcurves with zero events. ...

... In collaborative work with David Garc?a Alvarez (an Observatory PhD student now at Harvard) and John Butler, an extensive study of the RS CVn binary HR1099 was completed leading to two papers; the first on Doppler imaging and the second on flare activity. Spectra for the Doppler imaging were taken at two different sites, Kitt Peak National Observatory (KPNO), Arizona, and Mount Stromlo Observatory (MSO), Australia, during the 1998 MUltiSIte COntinuous Spectroscopic (MUSICOS) campaign. ...

... The Galactic low-mass X-ray binary GS 2023+338 was discovered during the burst on May 22, 1989 with the Japanise satellite Ginga (aka Galaxy). The flux reached 17 crabs (this unit of flux measurement is an bright X-ray source, Crab Nebula) at 10-35 keV. ... No other radio telescope worldwide carried out multi-frequency measurements. ... Upon 14 days the radio flux fell below the detection level at the RATAN-600 in relation to the decrease of the X-ray flux. ...

From the first published z > 3 survey of 21-cm absorption within the hosts of radio galaxies and quasars, we found an apparent dearth of cool neutral gas at high redshift. ... This indicates that he non-detection of 21-cm absorption is not due to the sensitivity limits of current radio telescopes, but rather that the lines-of-sight to the quasars, and probably the bulk of the host galaxies, are devoid of neutral gas. | ...

K-band Arcetri Obscured Supernova Search . What is the KAOSS Project? W hat is the KAOSS Project? Some recent surveys aimed at detecting Supernovae (SNe) in the optical have found that starburst galaxies do not show evidence for an enhanced SN rate, with respect to quiescent galaxies (Richmond et al. ... A similar result was obtained by Navasardyan et al. (2001) who looked for SNe in interacting galaxies, finding no evidence for correlations between SN rate and galaxy properties. ...

... In this activity, students will observe that the faintest stars which they can see in the sky are affected by many things: the adaptation of their eyes to the dark, the presence of clouds or haze, the time of year, and the presence of light pollution. General Information . ... After completing this activity, students should have a better understanding of the practical processes for dealing with the light pollution problem and with other environmental and societal issues. << previous page | ...

... Science . ... Science Users Information > Science Activities > APEX Science Verification > SHFI . ... Observing Facilities . ... Observing with ESO Telescopes . ... Telescope Time Allocation . ... ESO Data . ... The Science Verification (SV) observations of the APEX Swedish Heterodyne Facility Instrument were observed in March 2008. ... A selection of the APEX-1 proposals listed below have been observed during the week of joint SV observations in March 2008, and later during the ESO time of period...

... Precisely one month ago, on 11 July 2009, the last active area of the new solar cycle disappeared from the surface of the Sun. Over the 30 days following this, neither observers on Earth nor devices in space have been able to detect the emergence of any sunspots. ... Therefore, it seems that our star has once again returned to a state of deep solar "winter", following several sparks of activity in May-June 2009. ... To date, this period has lasted 30 days. ...

In this gallery are many images of Low Surface Brightness Galaxies which have recently been discovered and analyzed. ... The central surface brightness of this galaxy is 24.28 . Malin 2 This galaxy is another huge disk galaxy with a scale length of 15 kpc and a redshift of 15000 km/a. The high surface brightness knot in one of its spiral arms actually has the same color, luminosity and H-alpha equivalent width as the entire Large Magellanic Cloud . ... Truly it is a Low Surface Brightness Galaxy. ...

XMM-Newton CCF Release Note XMM- CCF -REL-176 RGS QUANTUMEF Shortest-Wavelength Correction Factors A.M.T. Pollock July 27, 2004 1 CCF components Name of CCF VALDATE List of Blocks changed XSCS ag RGS1 QUANTUMEF 0013 1998-01-01T00:00:00 RGA EFFAREACORR NO SI1 SI2 SI3 SI4 SI7 RGS2 QUANTUMEF 0014 1998-01-01T00:00:00 RGA EFFAREACORR NO SI1 SI2 SI3 SI4 SI5 SI7 2 Changes Near the short-wavelength end of the RGS bandpass, the instrument ... The best- t power-law indices, , are shown. ...

... 2002 March 7 . Comet Ikeya-Zhang Brightens . ... Explanation: In the last week , Comet Ikeya-Zhang has become bright enough to be just visible to the unaided eye. Based on its present activity, observers are optimistic that Ikeya-Zhang will become substantially brighter. This composite color image from March 3rd, captured with a wide-field telescope, shows this active comet's bright, condensed coma and a delightful array of subtle structures in its developing tail. ... About APOD | ...

The Southern Sky in Warm Hydrogen . ... Credit Copyright: SHASSA Team , NSF Explanation: A robotic telescope with red sunglasses in Chile has been photographing the entire southern sky for years. The result, shown above , is the most complete sky map of the most common visible light emitted from the most abundant element in our Galaxy: hydrogen . A very specific red color emitted by warm ionized hydrogen was observed. ... NASA Web Site Statements, Warnings, and Disclaimers . ...

... Space Research Institute . Main . ... Main research and development work completed in 2010 and ready for implementation . Elaboration of automatic technology for analysis of abnormal changes of vegetation status based on satellite data . ... Satellite MODIS-Terra image, obtained on May, 17 2010. ... Main research and development work completed in 2009 and ready for implementation . Main research and development work completed in 2008 and ready for implementation ...

... Proposal Type: General Category: Sub-Category: Observation Category: Time Requested this semester: Hours already used for this pro ject: Additional Hours required to complete pro ject: Minimum Useful Time: Expected Data Storage: Prop osal Title: ABSTRACT: We have recently used the Arecibo telescope and the Mock spectrometer to make timing measurements of an ultracool dwarf (UCD), TVLM 513-46546, at 5 GHz. ... Not surprisingly, differential rotation has been detected in other stars. ...

... The ROSAT Bright Survey: II. Catalogue of all high-galactic latitude RASS sources with PSPC countrate CR > 0.2 s -1 . ... 1S We present a summary of an identification program of the more than 2000 X-ray sources detected during the ROSAT All-Sky Survey (Voges et al. 1999) at high galactic latitude, |b| > 30degr , with countrate above 0.2 s -1 . This program, termed the ROSAT Bright Survey RBS, is to more than 99.5% complete. ...

... Tonight's Sky . ... The Magazine . ... Observing . ... The double star 54 Leonis, spiral galaxy NGC 3198, and emission nebula NGC 3199 . ... Astronomy for Kids . ... Observing springtime deep-sky objects with a large telescope . ... Bright planets meet at dusk . ... Astronomy magazine subscribers can read the full article for free. ... Get instant access to subscriber content on Astronomy.com! ... Receive news, sky-event information, observing tips, and more from Astronomy's weekly email newsletter....

... R. A. PRESTON, D. D. MORABITO, J. G. WILLIAMS, J. FAULKNER, D. L. JAUNCEY, G. D. NICOLSON VLBI observations at 2.29 GHz with fringe spacings of about 3 milliarcsec have been performed on 1398 radio sources spread over the entire sky. 917 sources were detected, including 93% of the identified BL Lacertae objects, 86% of the quasars, and 36% of the galaxies. ... Arcsecond positions for 787 of the detected sources have been previously determined from the VLBI survey data (Morabito et al. ... Source...

BRIGHT OPTICAL FLASH FROM GRB 060117 - AN EXAMPLE OF EVENT DETECTED WITH OMC CLASS INSTRUMENT Д Д Petr Kubanek1,2 , Martin JelД inek3 , Michael Prouza4,5,6 , Rene Hudec1 , and Martin Nekola1 1 Astronomicky ustav Akademie ved Ceske republiky, Ondrejov, Czech Republic ДД Д 2 INTEGRAL Science Data Center, Chemin d'Ecogia 16, Versoix, Switzerland 3 Instituto de AstrofД isica de AndalucД (IAA-CSIC), Granada, Spain ... INTEGRAL GRBs are detected during -ray observations of knows sources. ...

... Astrophysics Group . ... Pulsars . ... Stars ? ... The array was designed to detect compact radio sources such as these by virtue of the fact that they would scintillate (twinkle) when observed from the Earth through the interplanetary medium ? ... One of Antony Hewish?s research students, Jocelyn Bell, was set the task of operating the telescope and inspecting the daily charts for the kind deflections in the trace which occurred when a scintillating source passed over the array. ...